html:-moz-full-screen {
  background: grey;
}

html:-webkit-full-screen {
  background: grey;
  width: 100%;
  height: 100%;
}

html:fullscreen {
  background: grey;
  width: 100% !important;
  height: 100% !important;
}

:not(:root):fullscreen::backdrop {
  background: whitesmoke;
}

.pear-full-screen {
  width: 100% !important;
  height: 100% !important;
}